[lld] cdd29f5 - [ELF, RISCV] Fix TLSDESC=>IE when there is no TLS section
via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 11 17:59:02 PDT 2024
Author: Fangrui Song
Date: 2024-07-11T17:59:00-07:00
New Revision: cdd29f5bd2f5e55ae116be1a912f0b036d7c98e7
URL: https://github.com/llvm/llvm-project/commit/cdd29f5bd2f5e55ae116be1a912f0b036d7c98e7
DIFF: https://github.com/llvm/llvm-project/commit/cdd29f5bd2f5e55ae116be1a912f0b036d7c98e7.diff
LOG: [ELF,RISCV] Fix TLSDESC=>IE when there is no TLS section
See the comment in handleTlsRelocation. For TLSDESC=>IE (the TLS symbol
is defined in another DSO), R_RISCV_TLSDESC_{LOAD_LO12,ADD_LO12_I,CALL}
referencing a non-preemptible label uses the `R_RELAX_TLS_GD_TO_LE` code
path.
If there is no TLS section, `getTlsTpOffset` will be called with null
`Out::tlsPhdr`, leading to a null pointer dereference. Since the return
value is used by `RISCV::relocateAlloc` and ignored there, just return
0.
LoongArch TLSDESC doesn't use STT_NOTYPE labels. The `if (..) return 0;`
is a no-op for LoongArch.
This patch is a follow-up to #79239 and fixes some comments.
Pull Request: https://github.com/llvm/llvm-project/pull/98569
Added:
Modified:
lld/ELF/Arch/RISCV.cpp
lld/ELF/InputSection.cpp
lld/ELF/Relocations.cpp
lld/test/ELF/riscv-tlsdesc.s
Removed:
################################################################################
diff --git a/lld/ELF/Arch/RISCV.cpp b/lld/ELF/Arch/RISCV.cpp
index faacc8f834be7..6af89ce3517b7 100644
--- a/lld/ELF/Arch/RISCV.cpp
+++ b/lld/ELF/Arch/RISCV.cpp
@@ -631,8 +631,8 @@ void RISCV::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
continue;
case R_RELAX_TLS_GD_TO_LE:
// See the comment in handleTlsRelocation. For TLSDESC=>IE,
- // R_RISCV_TLSDESC_{LOAD_LO12,ADD_LO12,CALL} also reach here. If isToIe is
- // true, this is actually TLSDESC=>IE optimization.
+ // R_RISCV_TLSDESC_{LOAD_LO12,ADD_LO12,CALL} also reach here. If isToLe is
+ // false, this is actually TLSDESC=>IE optimization.
if (rel.type == R_RISCV_TLSDESC_HI20) {
tlsdescVal = val;
isToLe = true;
diff --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index 4420be77f6685..12ab1f1eac808 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -660,6 +660,11 @@ static int64_t getTlsTpOffset(const Symbol &s) {
return s.getVA(0) + (tls->p_vaddr & (tls->p_align - 1)) - 0x7000;
case EM_LOONGARCH:
case EM_RISCV:
+ // See the comment in handleTlsRelocation. For TLSDESC=>IE,
+ // R_RISCV_TLSDESC_{LOAD_LO12,ADD_LO12_I,CALL} also reach here. While
+ // `tls` may be null, the return value is ignored.
+ if (s.type != STT_TLS)
+ return 0;
return s.getVA(0) + (tls->p_vaddr & (tls->p_align - 1));
// Variant 2.
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index da4724d8f6536..9ad180306bcd8 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -1399,8 +1399,8 @@ static unsigned handleTlsRelocation(RelType type, Symbol &sym,
// depending on the symbol being locally defined or not.
//
// R_RISCV_TLSDESC_{LOAD_LO12,ADD_LO12_I,CALL} reference a non-preemptible
- // label, so the LE optimization will be categorized as
- // R_RELAX_TLS_GD_TO_LE. We fix the categorization in RISCV::relocateAlloc.
+ // label, so TLSDESC=>IE will be categorized as R_RELAX_TLS_GD_TO_LE. We fix
+ // the categorization in RISCV::relocateAlloc.
if (sym.isPreemptible) {
sym.setFlags(NEEDS_TLSGD_TO_IE);
c.addReloc({target->adjustTlsExpr(type, R_RELAX_TLS_GD_TO_IE), type,
diff --git a/lld/test/ELF/riscv-tlsdesc.s b/lld/test/ELF/riscv-tlsdesc.s
index 935ecbddfbfff..6c0dd9a247a4e 100644
--- a/lld/test/ELF/riscv-tlsdesc.s
+++ b/lld/test/ELF/riscv-tlsdesc.s
@@ -37,6 +37,11 @@
# RUN: llvm-mc -triple=riscv32 -filetype=obj d.s -o d.32.o --defsym ELF32=1
# RUN: ld.lld -shared -soname=d.32.so -o d.32.so d.32.o --fatal-warnings
+## The output has a TLS reference but no TLS section.
+# RUN: llvm-mc -filetype=obj -triple=riscv64 a1.s -o a1.64.o
+# RUN: ld.lld -pie a1.64.o c.64.so -o a1.64
+# RUN: llvm-objdump --no-show-raw-insn -M no-aliases -Rd a1.64 | FileCheck %s --check-prefix=IE64A
+
# GD64-RELA: .rela.dyn {
# GD64-RELA-NEXT: 0x2408 R_RISCV_TLSDESC - 0x7FF
# GD64-RELA-NEXT: 0x23E8 R_RISCV_TLSDESC a 0x0
@@ -164,6 +169,17 @@
# IE32-NEXT: lw a0, 0x80(a0)
# IE32-NEXT: add a0, a0, tp
+# IE64A: OFFSET TYPE VALUE
+# IE64A-NEXT: 0000000000002340 R_RISCV_TLS_TPREL64 c
+# IE64A-EMPTY:
+## &.got[c]-. = 0x2340 - 0x1258 = 0x10e8
+# IE64A-LABEL: <.Ltlsdesc_hi2>:
+# IE64A-NEXT: addi zero, zero, 0x0
+# IE64A-NEXT: addi zero, zero, 0x0
+# IE64A-NEXT: 1258: auipc a0, 0x1
+# IE64A-NEXT: ld a0, 0xe8(a0)
+# IE64A-NEXT: add a0, a0, tp
+
#--- a.s
.macro load dst, src
.ifdef ELF32
@@ -202,6 +218,15 @@ a:
b:
.zero 1
+#--- a1.s
+## a.s without TLS definitions.
+.Ltlsdesc_hi2:
+ auipc a4, %tlsdesc_hi(c)
+ ld a5, %tlsdesc_load_lo(.Ltlsdesc_hi2)(a4)
+ addi a0, a4, %tlsdesc_add_lo(.Ltlsdesc_hi2)
+ jalr t0, 0(a5), %tlsdesc_call(.Ltlsdesc_hi2)
+ add a0, a0, tp
+
#--- c.s
.tbss
.globl c
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